Valve means for oil wells



July 3, 1956 R. H. HILL 2,752,861

VALVE MEANS FOR OIL WELLS Filed Nov. 12, 1952 3 Sheets-Sheet l INVENTOR.

July 3,1956 R. H. HILL 2,752,861

VALVE MEANS FOR OIL WELLS Filed Nov. 12, 1952 3 Sheets-Sheet 2 IN V EN TOR.

Jimmy E 1956 R. H. HILL VALVE MEANS FOR OIL WELLS 3 Sheets-Sheet 5 Filed Nov. 12, 1952 INVENTOR.

United States Patent VALVE MEANS FOR OIL WELLS Robert H. Hill, Fort Wayne, lnd., assignor, by mesne assignments, to Perfect Circle Corporation, Hagerstown, Ind., a corporation of Indiana Application November 12, 1952, Serial No. 319,995

16 Claims. (Cl. 103-421) This invention relates to improvements in oil well pumping apparatus and more particularly to a novel drain valve means for permitting complete drainage of the production tubing prior to the removal of the pump and tubing from the well casing.

In oil wells of the low pressure type, a string of tubing extends downwardly through the well casing and oil is pumped out of the well through the tubing by means of a pump located adjacent the bottom of the well. The pump normally includes a foot or check valve or other equivalent valve means to prevent unintentional flow of oil downwardly through the tubing so that in the event that the pump is stopped for any reason the fluid head of oil in the tubing will not be lost. Frequently, however, it is desired for various reasons to interrupt the production of a well in order to remove the pump and the entire string of tubing from the well. In such circumstances, unless the head of oil can first be drained or otherwise removed from the tubing, it becomes necessary to remove the tubing while the latter is filled with oil. Obviously, this practice of pulling a wet string is highly dangerous and objectionable.

Accordingly, a primary object of the invention is to provide novel drain valve means for use with an oil well pumping apparatus preparatory to removing the production tubing whereby to permit drainage of oil from the tubing which is normally filled with oil.

A further object of the invention is to provide novel drain means for draining oil from the production tubing of an oil well and particularly adapted for use with a reversible pumping apparatus capable of repressurizing a well.

An additional object of the invention is to provide novel tubing drain means, as described in the preceding objects, in combination with auxiliary valve means for assisting the starting of the well pump by temporarily removing from the pump the hydrostatic pressure due to the head of oil in the well tubing.

Another object of the invention is to provide a novel combination as described in the preceding object with further provision for rendering said auxiliary valve means either active or inactive, as desired.

Other objects and advantages of the invention will become evident from the subsequent detailed description taken in conjunction with the accompanying drawings, wherein:

Fig. l is a fragmentary elevational view on a reduced scale of a complete oil well pumping apparatus embodying my invention and showing the apparatus in position in a well casing;

Fig. 2 is a vertical sectional view on an enlarged scale as taken along the line 22 of Fig. 4 and showing the details of the drain valve means illustrated in Fig. l and constituting one specific embodiment of my invention;

Fig. 3 is a view similar to Fig. 2, but showing the parts of the device in a different position;

ice

Fig. 4 is a transverse cross-sectional view as taken along the line 4-4 of Fig. 2;

Fig. 5 is a vertical sectional view showing a modified form of the invention; and

Fig. 6 is a vertical sectional View showing still another modification of the invention.

In Fig. l, the invention is illustrated. in conjunction with a reversible oil well pumping apparatus of the type described in detail in my copending application Serial No. 247,227, filed September 19, 1951. This type of apparatus is particularly useful when it is desired to effect alternate or intermittent periods: of production and pressurizing or purging of an oil well. In general, this apparatus comprises the combination of a reversible rotary pump and a reversible electric motor connected closely adjacent the pump so that the entire apparatus may be positioned adjacent the bottom of the well. When the production of the well diminishes to an undesirably low level, the operation of the apparatus can be reversed to pump oil or other suitable purging fluid downwardly and under pressure through the production tubing into the well whereby to purge or otherwise remove obstructions fromthe production strata and the fluid intake of the apparatus. A suitable packer is provided in the well casing for confining the fluid pressure to the lower portion of the well during the pressurizing periods so that pressures greater than the head due to the depth of the well can be obtained.

Although the invention in its preferred embodiment is described herein in connection with a reversible pumping apparatus of the foregoing type, it will be understood that the invention is also adapted for use in other types of oil well pumping apparatusv where similar problems are encountered.

Referring now to Fig. l, the fragmentary lower portion of an oil well casing 6 is shown and the surrounding earth formation is indicated diagrammatically at 7. It will be understood that the casing 6 extends in the usual manner from the ground level to the bottom of the well although neither of the extreme ends of the casing are illustrated in the drawing. A pumping apparatus is shown in position in the well casing and comprises generally a reversible motor section A and a reversible pump section B connected in end-to-end relation for fluid flow therebetween. An intake (not shown) is provided at the bottom of the pumping apparatus, and an outlet pipe 8 extends upwardy from. the top of the pumping apparatus. The outlet 8 is connected through a valve unit 9, which forms the principal feature of the present invention, to a string of tubing 10 which extends through the well casing to the ground level. Suitable electrical conductors comprising a cable 11 extend from the ground level downwardly through the casing 6 to the motor section A for operating the latter.

During production, the reversible motor section A is operated so that the reversible pump section B draws oil from the bottom of the well casing and discharges the oil through suitable passageways in the motor section A and through the valve unit 9 to the tubing 10 which is connected to a tank or other storage facilities at the ground level. When the producing formation and/or the intake become clogged or obstruct-ed to an objectionable degree, as indicated by a low volume of oil issuing from the well, the motor is reversed and the pump is thereby operated in reverse fashion so that oil or other suitable purging material is pumped downwardly and is discharged from the pump under pressure. In order to insure that the oil or other material is forcibly injected into the adjacent producing formation at the bottom of the well, a portion of the pump section B is fitted with an expansible packer 12 of a type adapted to resist upward pressure.

In the embodiment shown in the drawing, the packer 12 is of a conventional type comprising an axially compressible rubber sleeve. The rubber sleeve is secured aroundthe upper portion of the pump casing, and as the apparatus is initially installed in the well casing the rubber sleeve is retracted. However, by means of a telescoping action, well known in the packer art, slidable sections of the pump casing are shifted after the apparatus is in place in the well and the rubber sleeve is compressed and bulged outwardly into tight fitting sealed relation with the inside of the well casing 6, as shown in Fig. 1. In this manner, it will be understood that the packer 12 eifectively segregates the lower portion of the well so as to define a reservoir space between the packer and the bottom of the well. The rubber sleeve comprising the packer 12 is disposed only around the upper portion of the pump so that the lower end of the pump extends below the packer into the reservoir space. Thus, when oil or other purging material is pumped downwardly into the well under pressure, the reservoir space is sealed at its upper end by the packer 12 and the oil is, therefore, readily forced under high pressure into the obstructed producing formation or strata for purging and cleaning the same. At the same time, the pump intake is also cleaned and flushed out.

A portion of the pump section B in Fig. l is broken away to show that this portion of the apparatus comprises a reversible pump of the positive displacement type in which there is an elongated rotary pumping member having driving connections with the motor of the device for operation in either a clockwise or counterclockwise direction. More particularly, the apparatus comprises the progressing cavity type pump known commercially as the Moyno pump and including an elongated female helical member 13 which constitutes the stator of the pump and an elongated male helical member 14 mounted in the female member and constituting the rotor of the pump. The outer member or stator is provided with one helical thread more than the inner or rotor, and the two members are so arranged and shaped that every thread of the rotor is constantly in contact with the stator in any transverse section through the pump. This relation of the rotor and stator is such that a plurality of closed spaces or cavities are defined between the two members because of the difference in the number of threads on each member. When the rotor is rotated relative to the stator, the cavities or spaces between the members are displaced in a longitudinal direction with the result that a fluid material can be axially transported between the two members to obtain the desired pumping efiect. Reference is made to U. S. Patent Numbers 1,892,217 and 2,028,407, for a detailed consideration of the theory and operation of the progressing cavity type of pump.

In Fig. 1 a portion of the motor section A has also been broken away to reveal the provisions which have been made for preventing loss of fluid head fhen the pump is stopped for any reason. If the pump is stopped during a production period, it will be understood that the hydrostatic pressure of the head of oil in the production tubing above the pumping unit will tend to force oil downwardly through the pump thereby causing the latter to motor with consequent loss of fluid head. In the apparatus shown by way of illustration, such undesirable motoring of the pump is prevented by means of a magnetic brake which holds the pump rotor 14 in fixed position relative to the pump stator 13 whenever the motor and pump are stopped for any reason. Thus, the upper end of the rotor shaft of the motor, indicated at 16 in. Fig. 1, extends upwardly through a bearing 17 mounted in a partition 18. The upper extremity of the rotor shaft 16 is formed with splines for mounting a shiftable brake member 19 in non-rotatable but axially shiftable relation with respect to the shaft 16. The outer periphery of the brake member 19 has an angular braking surface 21 which is adapted to coact with a complementary braking surface 22 formed in the partition structure 18. A thrust washer 23 is mounted at the end of the splined portion of the rotor shaft 16 and a helical spring 24 coacts between the thrust washer 23 and the axially shiftable brake member 19 for normally urging the latter into braking engagement with the braking surface 22.

A magnet 26 having pole pieces 27 and 28 and an energizing winding 29* is mounted above the brake member 19 for releasing the latter. The shiftable brake member 19 is formed from a magnetically attractable metal, and the magnet winding 29 is connected in series (by means not shown) with the current supplied to one phase of the motor so that whenever the motor is in operation the magnet 26 will be energized and the brake member 19 will be held in released position against the magnet poles 27 and 28 and out of engagement with the stationary braking surface 22 regardless of the direction of the rotation of the apparatus. However, if the current to the motor is interrupted for any reason so that the operation of the pump ceases, it will be seen that the brake member 19 will be immediately released by the magnet 26 and the spring 24 will then automatically force the brake member 19 into braking engagement with the braking surface 22. With the rotor shaft 16 thus held against movement by the magnetic brake described above, it will be understood that the pump rotor 14 cannot move relative to the pump stator 13 and consequently it is impossible for the fluid head above the pump to flow through the pump structure. In other words, the pump itself then serves as a valve and there is no opportunity for the fluid pressure in the tubing to eflect motoring of the pump with consequent drainage of the fluid to the bottom of the well.

Assuming that the apparatus shown in Fig. 1 has been in operation for a substantial period of time so that the entire string of tubing 10 is filled with oil and assuming that it is then desired to remove the motor and pump unit together with the tubing from the well, it will be seen that unless some convenient means is provided for draining the production tubing it will be necessary to pull a wet string. The device designated generally at 9 in Fig. 1 provides the desired means for draining the pro duction tubing prior to removing the same, and this structure will now be described in detail with reference particularly to Figs. 2, 3, and 4.

The device 9 comprises a landing nipple 31 which is threaded at its upper end for connection by means of a coupling 32 with the tubing 10. The lower end of the landing nipple 31 is also threaded, as at 33, for connection with the outlet pipe 8, a pair of grooves 34 being provided above and below the threads 33 for the installation of sealing rings to insure a fluid tight connection. A plurality of radial ports or drain openings 36 are provided in the side wall of the landing nipple 31, and the exterior of the nipple below the ports 36 is grooved, as at 37, to facilitate fishing the pump unit out of the well in the event that the tubing string 10 is broken.

Disposed concentrically within the landing nipple 31 is a slidable tubular core or mandrel 38 having a relatively tight frictional fit within the nipple 31. The mandrel 38 has a eenter portion 39 of reduced diameter adapted to overlie the ports 36, and a plurality of sealing rings 41 are carried by the mandrel above and below the reduced portion 39 for sealing the ports 36 against the passage of fluid therethrough when the mandrel is in the position shown in Fig. 2. The lower end of the mandrel 38 is formed with a plurality of integral resilient spring fingers 42 adapted to coact with an integral shoulder 43 formed at the inner surface of the landing nipple 31 whereby the mandrel 38 is normally retained in the sealing position illustrated in Fig. 2. However, the spring fingers 42 being resilient and compressible are deflecta'ble inwardly to permit upward shifting movement of the mandrel 38 relative to the landing nipple 31 so that the lower end of the mandrel 38 can be moved above the ports 36, as illustrated in Fig. 3, in order to permit the passage of fluid through the latter as hereinafter described in detail.

Mounted at the upper end of the mandrel 38 is a cage member 44 having a threaded connection '46 with the mandrel. The cage 44 has an external shoulder 47 which coacts with a complementary shoulder portion 48 at the interior of the nipple 31 for limiting the extent of downward movement of the mandrel 38 relative to the landing nipple and thereby insuring the proper sealing of the ports 36 when the mandrel is shifted to sealed position. The cage 44 also has a central coaxial opening or bore 49 at its upper end and is also provided with a plurality of radial slots 51 spaced circumferentially around the cage, four such slots 51 being shown in this instance (Fig.4).

Shifting movement of the mandrel 38 for opening the ports 36 may be eifected by means of a combined actuating member and check valve member 52 having an enlarged valve plug 53 disposed within the cage 44 and an elongated valve stem 54 extending loosely through the opening 49 and upwardly beyond the cage 44. The upper end of the valve stem 54 has threaded thereto a grasping head or nut 56 having a tapered under-cut portion 57 to facilitate grasping of the nut 56 by a suitable tool. A cross pin 58 extends through the grasping head 56 and the end portion of the valve stem 54 to insure a rigid connection therebetween. It will readily be understood that by extending a suitable tool downwardly from the ground level through the Well tubing and grasping the head portion '56, an upward pull can then be exerted on the valve member 52 which in turn pulls upwardly on the cage 44 and thus shifts the mandrel 38 to the position shown in Fig. 3 for clearing the drainage ports 36 in the landing nipple. With the ports 36 thus opened, it will be seen that fluid communication is established between the interior of the mandrel 38 and the annular space between the well casing 6 and the tubing 10. Thus, the head of oil in the production tubing 10 can drain by gravity downwardly through the radial slots 51 in the cage 44 and thence through the mandrel 38 and the ports 36 into the tubing-casing annulus. It will be understood, of course, that in such instance the expansible packer 12 will have been released in order to permit the pumping unit to be removed from the well and accordingly the oil can readily pass from the tubing casing annulus into the producing formation in the ground.

As seen in full lines in Figs. 2 and 3, the movable member 52 is retained in its upper position with the valve plug 53 in spaced relation above the upper end of the mandrel 38 so as to permit free flow of oil through the mandrel 38 in either the Fig. 2 or Fig. 3 positions thereof. The retention of the valve plug 53 in the above described relation is accomplished by means of a plurality of radially disposed retainer elements or detents 59 carried in the solid partition portions, indicated at 61, of the cage 44 intermediate the slots 51. The inner ends of the detents 59 are rounded, as at 62, and are adapted to be received in retaining engagement within a circumferential groove 63 provided around the valve plug 53. The outer ends of the detents 59 have enlarged head portions 64 disposed within a circumferential groove 66 extending around the exterior of the slotted portion of cage 44, and a one-piece generally circular spring element or resilient band 67 extends around the groove 66 in engagement with the head portions 64 of the detents 59 for releasably urging the latter into coacting engagement with the valve plug groove 63. Thus, the detents 59 normally hold the valve member 52 in its upper position under the resilient pressure of the spring element 67.

However, the valve member 52 in addition to its function as an actuating or grasping device for effecting shifting movement of the mandrel 38 also serves another highly useful purpose in connection with. the starting of the electric motor and pump unit. In the event that the motor and pump unit is stopped for any reason dur ing a production period and it is then desired to start up the unit again, the hydrostatic pressure of the fluid head in the tubing string 10 eXerts a tremendous starting load on the motor section A. However, according to my invention, the member 52 can be rendered operative or active :as a check valve by striking the grasping head 56 with a downward blow so that the detents 59 are cammed outwardly against the action of the spring element 67 thereby releasing the valve member 52 and permitting the latter to drop by gravity into the closed position illustnated in dotted lines in Fig. 2. In this position of the valve member 52, the tapered portion of the valve plug 53 fits against a corresponding tapered seat portion 68 at the upper end of the mandrel 58 whereby to close the. latter. Obviously, the pressure of the head of oil above the valve member 52 will serve to hold the valve plug 53 tightly against the seat 68 so that the pressure due to the hydrostatic head above the valve plug 53 is elfectively removed from the pump unit B and the starting load of the motor section A is thereby greatly diminished.

Once the motor and pump are in operation the pressure of the upwardly flowing fluid through the mandrel 58 will readily lift the valve plug 53 from the seat 68 to permit production flow of the well in the normal manner. If the upward pressure of the oil is sufiiciently great, the valve member 52 may be returned to its retained relation with the detents 59. However, if the upward pressure is insufiicient to accomplish the return of the valve member 52 to its retained open position, the valve may be readily pulled upwardly to an inoperative position by means of a tool grasping the head 56, and the unit will then be in position for repressurizing of the well by downward flow of pressurizing fluid. When it is desired to switch back again to production, the valve member 52 may be returned to operative relation by striking the head 56 as described above so that the motor section A can be started up in reverse direction without an excessive starting load.

In Fig. 5 I have shown a modified form of the invention usually used where repressurizing is not required and in which there is not retainer means for normally retaining the check valve member in inoperative position. Thus, in Fig. 5 the device comprises a landing nipple 71 having attached thereto a coupling 72 and provided with radial drain ports 73. A concentric shiftable mandrel 74 of slightly diiferent design is shown in position within the landing nipple 71. In this instance, upper and lower sets of V packing 75 enclosed by suitable packing adapter rings, are provided in peripheral recesses 76 in the mandrel 74 and are adapted to be located above and below the drain ports 73 of the landing nipple for sealing these ports. Integral spring fingers 77 are provided at the lower end of the mandrel 74 for coaction with the lower end of the landing nipple 71 in the same general manner as in the previously described form of the invention.

A cage 78 is threaded to the upper end of the mandrel 74 and is provided with a plurality of radial slots 79 in substantially the same general relation as hereinbefore described. The device also comprises a movable check valve member 81 having a valve plug portion 82 adapted to seat against the upper end of the mandrel 74, as before, and also having an elongated valve stem 83 extending through a central bore 84 at the upper end of the cage 78. A grasping head 86 is secured to the valve stem 83 for the purpose of permitting the valve stem to be grasped by a suitable tool and pulled upwardly to shift the mandrel 74 to its open position relative to the drain ports 73. However, in this case the movable check valve member 81 normally remains in the closed position shown in Fig. 5 so that complete drainage: of the production tubing into the tubing-casing annulus can be effected 7 only while the valve member 81 is held manually in open position by a grasping tool which engages the head 86. It will also be apparent that, if desired, the entire mandrel 74 can be removed bodily from the landing nipple 71 to permit drainage of the production tubing. Although this form of the invention does not conveniently permit pumping of fluid downwardly under pressure into the well, it finds considerable utility in connection with many oil production systems wherein oil is pumped out of the well since it does permit complete drainage of the production tubing when desired and also provides the check valve feature for reducing the starting load on the pump.

In Fig. 6 I have shown still another embodiment of the invention wherein the movable check valve feature is entirely omitted. In this form of the invention the'landing nipple 71 and the mandrel assembly '74 is generally the same as shown in Fig. 5. However the cage construction at the top of the mandrel 74 differs somewhat. In this instance the cage, designated at 87, has a plurality of radial slots 88 for the passage of fluid, but the upper end of the cage is formed with a solid integral axial extension 89 having an enlarged grasping head portion 91. Thus, with this embodiment of the invention fluid can be pumped either upwardly or downwardly at will and at the same time the mandrel 74 can be shifted when desired by means of the grasping head 51 to permit drainage of the production tubing through the ports 73 into the tubing-casing annulus.

Although the invention has been described with particular reference to certain specific structural embodiments, it will be understood that various modifications may be resorted to without departing from the scope of the invention as defined in the appended claims.

I claim:

1. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and defining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means comprising a landing nipple adapted to be interposed in the tubing above the pump and having aperture means in the side wall thereof adapted to communicate with the tubing-casing annulus, an axially shiftable tubular mandrel disposed within said nipple, sealing means coacting between said nipple and said mandrel for normally sealing said aperture means, means at one end of said mandrel adapted to be grasped for effecting axial shifting movement thereof, and resilient retainer means mounted on the opposite end of said mandrel and coacting with said nipple for normally retaining the mandrel in sealing relation but deflectable to permit axial shifting of the mandrel for providing flow communication between the tubing and the tubing-casing annulus through the bore of said mandrel and through said aperture means.

2. The structure of claim 1 further characterized in that said nipple is provided with internal shoulder means, and said resilient retainer means comprises a plurality of spring fingers extending axially from said opposite end of said mandrel and normally engaging said shoulder means but defiectable inwardly from said shoulder means in response to axial shifting of said mandrel.

3. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and defining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means comprising a landing nipple having fastening means at its opposite ends for rigidly interposing the nipple in the tubing above the pump and having aperture means in the side wall thereof adapted to communicate with the tubingcasing annulus, an axially shiftable tubular mandrel disposed within said nipple for movement between closed and drain position, said mandrel when in closed position overlying said aperture means and when in drain position having its lower end displaced axially above said aperture means for clearing the same, sealing means coacting between said nipple and said mandrel for normal- 1y sealing said aperture means when said mandrel is in closed position, a cage member secured to the upper end of said mandrel and having a plurality of radial slots permitting the passag of fluid therethrough into the bore of said mandrel, and a grasping head operatively coacting with said cage member in coaxial relation with said mandrel and adapted to be grasped for effecting axial shifting movement of the mandrel to drain position whereby to permit drainage of fluid from the tubing through said and said mandrel and thence through said aperture means into the tubing-casing annulus.

4. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and defining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means comprising a landing nipple adapted to be interposed in the tubing above the pump and having aperture means in the side wall thereof adapted to communicate with the tubing-casing annulus, an axially shiftable tubular mandrel disposed within said nipple, sealing means coacting between said nipple and said mandrel for normally sealing said aperture means, a cage member secured to one end of said mandrel and having a plurality of radial slots permitting the passage of fluid therethrough, a grasping head operatively coacting with said cage member in coaxial relation with said mandrel and adapted to be grasped for elfecting axial shifting movement of the mandrel, and resilient retainer means mounted on the opposite end of said mandrel and coacting with said nipple for normally retaining the mandrel in sealing relation but defiectable to permit axial shifting of the mandrel for providing flow communication between the tubing and the tubing-casing annulus through the bore of said mandrel and through said aperture means.

5. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and defining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means being adapted to be interposed in the tubing above the pump and having aperture means in the side thereof adapted to communicate with the tubing-casing annulus, said valve means including a shiftable tubular mandrel having means for normally sealing said aperture means, check valve means including a movable valve member adapted to close said mandrel for preventing the flow of fluid therethrough in one direction and an actuating portion on said valve member adapted to be manipulated for moving the valve member between open and closed positions relative to said mandrel.

6. The structure of claim 5 further characterized in that said mandrel is provided with resilient retainer means for normally retaining the mandrel in sealing relation but defiectable to permit axial shifting of the mandrel.

7. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and defining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means comprising a landing nipple adapted to be interposed in the tubing above the pump and having aperture means in the side wall thereof adapted to communicate with the tubing-casing annulus, a shiftable tubular mandrel disposed within said nipple and having means for normally sealing said aperture means, a shiftable check valve member adapted to seat against one end portion of said mandrel for preventing the flow of fluid therethrough in one direction, cage means secured to said one end portion of said mandrel for limiting the extent of movement of said valve member, and actuating means secured to said valve member beyond said cage means and adapted to be grasped for effecting shifting movement of said mandrel.

8. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and defining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means comprising a landing nipple adapted to be interposed in the tubing above the pump and having aperture means in the side wall thereof adapted to or mmunicate with the tubingcasing annulus, a shiftable tubular mandrel disposed within said nipple and having means for normally sealing said aperture means, a radially slotted cage secured to one end of said mandrel and provided with an axial open ing therethrough, a shiftable check valve member having an elongated stem portion extending through said opening and a valve portion at one end thereof within said cage and adapted to seat against said one end of said mandrel for preventing the flow of fluid therethrough in one direction, said cage limiting the extent of movement of said valve member away from said mandrel, and a grasping head secured at the opposite end of "said stem portion beyond said cage and adapted to be grasped for effecting shifting movement of the mandrel.

9. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and defining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means comprising a landing nipple adapted to be interposed in the tubing above the pump and having aperture means in the side wall thereof adapted to communicate with the tubing-casing annulus, a shiftable tubular mandrel disposed within said nipple and having means for normally sealing said aperture means, a shiftable check valve member adapted to seat against one end portion of said mandrel for preventing the flow of fluid therethrough in one direction, cage means secured to said one end portion of said mandrel for limiting the extent of movement of said valve member, actuating means secured to said valve member beyond said cage means and adapted to be grasped for effecting shifting movement of said mandrel, and resilient retainer means adjacent the opposite end of said mandrel coacting with said nipple for normally retaining the mandrel in sealing relation but deflectable to permit shifting of the mandrel for providing flow communication between the tubing and the tubing-casing annulus through said aperture means.

10. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and defining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means being adapted to be interposed in the tubing above the pump and having aperture means in the side thereof adapted to communicate with the tubing-casing annulus, said valve means including a shiftable tubular mandrel having means for normally sealing said aperture means, check valve means including a movable valve member adapted to close said mandrel for preventing flow of fluid therethrough in one direction, and retainer means operable independently of the direction of fluid flow through said mandrel for releasably holding said valve member in open position relative to said mandrel.

11. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and defining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means com prising a landing nipple adapted to be interposed in the tubing above the pump and having aperture means in the side wall thereof adapted to communicate with the tubingcasing annulus, a shiftable tubular mandrel disposed within said nipple and having means for normally sealing said aperture means, check valve means mounted adjacent one end of said nipple and including a shiftable valve member adapted to close one end of said mandrel for preventing the flow of fluid therethrough in one direction, said valve member being movable in response to the flow of fluid for opening said one end of said mandrel to permit flow therethrough in the opposite direction, and retainer means for releasably holding said valve member in open position relative to said mandrel whereby to render said valve member inoperative.

12. Valve means for an oil well apparatus of the type having anouter easing, tubing within the casing and de fining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means comprising a landing nipple adapted to be interposed in the tubing above the pump and having aperture means in the side wall thereof adapted to communicate with the tubing-casing annulus, a shiftable tubular mandrel disposed within said nipple and having means for normally sealing said aperture means, a cage secured to one end of said mandrel and provided with radial openings for the passage of fluid therethrough, a shiftable valve memher having an elongated stern extending coaxially through said cage and an enlarged valve plug disposed within said cage and adapted to seat against one end of said mandrel for preventing fluid flow through the latter in one direction, said valve plug having a circumferential groove therein, a plurality of movable detents carried by said cage for coaction with said groove, and means resiliently urging said detents into coacting engagement in said groove for releasably retaining said valve member in open unseated relation wtih respect to said mandrel.

13. The device of claim 12 further characterized in that said detents are spaced circumferentially around said cage and said last-named means comprises a spring member extending around the periphery of said cage and engaging said detents.

14. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and defining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means comprising a landing nipple adapted to be interposed in the tubing above the pump and having aperture means in the side wall thereof adapted to communicate with the tubingcasing annulus, a shiftable tubular mandrel disposed within said nipple and having means for normally sealing said aperture means, check valve means mounted adjacent one end of said nipple and including a shiftable valve member adapted to close one end of said mandrel for preventing the flow of fluid therethrough in one direction, said valve member being movable in response to the flow of fluid for opening said one end of said mandrel to permit flow therethrough in the opposite direction, retainer means for releasably holding said valve member in open position relative to said mandrel whereby to render said valve member inoperative, and resilient means at the opposite end of said mandrel coacting with said nipple for normally retaining the mandrel in sealing relation but deflectable to permit shifting of said mandrel for providing communication between the tubing and the tubing-casing annulus through said aperture means, said valve member having a grasping portion adapted to be grasped for effecting shifting movement of the mandrel.

15. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and defining an annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means comprising a landing nipple adapted to be interposed in the tubing above the pump and having aperture means in the side wall thereof adapted to communicate with the tubing casing annulus, a shiftable tubular mandrel disposed within said nipple and having means for normally sealing said aperture means, a cage secured to the upper end of said mandrel and having radial slots and an axial opening, a check valve member comprising an enlarged valve plug within said cage and an elongated stem extending freely through said opening, said valve plug being adapted to seat against the upper end of said mandrel for preventing the passage of fluid downwardly therethrough and said valve member being shiftable upwardly only in response to the upward flow of fluid upwardly through the mandrel and through said slots into the tubing, said valve plug being larger than said opening whereby to limit upward movement of the valve member, and a grasping head secured to said valve stem outside said cage whereby to prevent said mandrel to be shifted relative to said nipple.

16. Valve means for an oil well apparatus of the type having an outer casing, tubing within the casing and definingan annular space therebetween, and a pump for withdrawing oil through the tubing, said valve means comprising a landing nipple adapted to be interposed in the tubing above the pump and having aperture means in the side wall thereof adapted to communicate with the tubingcasing annulus, a shiftable tubular mandrel disposed within said nipple and having means for normally sealing said aperture means, a tubularmember secured at one end thereof to one end of said mandrel and having an integral solid grasping head disposed coaxially at the other end thereof, said grasping head being adapted to be grasped for effecting shifting movement of said mandrel and said tubular member having radial opening, and resilient re- References Cited in the file of this patent UNITED STATES PATENTS 1,323,379 Rigby Dec. 2, 1919 1,608,167 CroWell et a1 Nov. 23, 1926 2,270,952 Lee Ian. 27, 1942 2,363,644 Collins Nov. 28, 1944 2,572,388 Redpath Oct. 23, 1951 

1. VALVE MEANS FOR AN OIL WELL APPARATUS OF THE TYPE HAVING AN OUTER CASING, TUBING WITHIN THE CASING AND DEFINING AN ANNULAR SPACE THEREBETWEEN, AND A PUMP FOR WITHDRAWING OIL THROUGH THE TUBING, SAID VALVE MEANS COMPRISING A LANDING NIPPLE ADAPTED TO BE INTERPOSED IN THE TUBING ABOVE THE PUMP AND HAVING APERTURE MEANS IN THE SIDE WALL THEREOF ADAPTED TO COMMUNICATED WITH THE TUBING-CASING ANNULUS, AN AXIALLY SHIFTABLE TUBULAR MANDREL DISPOSED WITHIN SAID NIPPLE, SEALING MEANS COACTING BETWEEN SAID NIPPLE AND SAID MANDREL FOR NORMALLY SEALING SAID APERTURE MEANS, MEANS AT ONE END OF SAID MANDREL ADAPTED TO BE GRASPED FOR EFFECTING AXIAL SHIFTING MOVEMENT THEREOF, AND RESILIENT RETAINER MEANS MOUNTED ON THE OPPOSITE END OF SAID MANDREL AND COACTING WITH SAID NIPPLE FOR NORMALLY RETAINING THE MANDREL IN SEALING RELATION BUT DEFLECTABLE TO PERMIT AXIAL SHIFTING OF THE MANDREL FOR PROVIDING FLOW COMMUNICATION BETWEEN THE TUBING AND THE TUBING-CASING ANNULUS THROUGH THE BORE OF SAID MANDREL AND THROUGH SAID APERTURE MEANS. 